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Lithium-sulfur (Li-S) batteries are in the spotlight because their outstanding theoretical specific energy is much higher than those of the commercial lithium ion (Li-ion) batteries. Li-S batteries are tough competitors for futuredeveloping energy storage in the fields of portable electronics and electric vehicles. However, the severe "shuttle effect" of the polysulfides and the serious damage of lithium dendrites are main factors blocking commercial production of Li-S batteries. Owing to their superior nanostructure, electrospun nanofiber materials commonly show some unique characteristics that can simultaneously resolve these issues. So far, various novel cathodes, separators, and interlayers of electrospun nanofiber materials which are applied to resolve these challenges are researched. This review presents the fundamental research and technological development of multifarious electrospun nanofiber materials for Li-S cells, including their processing methods, structures, morphology engineering, and electrochemical performance. Not only does the review article contain a summary of electrospun nanofiber materials in Li-S batteries but also a proposal for designing electrospun nanofiber materials for Li-S cells. These systematic discussions and proposed directions can enlighten thoughts and offer ways in the reasonable design of electrospun nanofiber materials for excellent Li-S batteries in the near future.or conducting coagulation bath) is placed against the capillary. A thin polymer fiber membrane is deposited on the collector. The electrospun nanofibers have big potential for developing the outstanding energy storage systems due to their high surface area and excellent surface-to-volume ratio which can offer numerous active sites and controllable porous structure to buffer the huge volume changes during battery cycling and infiltrate the electrolyte. [18] Electrospun nanofiber membranes possess high porosity, large specific surface area, and controllable pore size, which will block "shuttle effect" of polysulfides and enhance the wettability for electrolytes. [19] Electrospinning technique and carbonization process are facile to manufacture freestanding nanofiber fabrics with controllable porous architecture and outstanding electrical conductivity. Electrospun porous nanofibers can come into a reservoir-like matrix for the reserve of active materials. First, the hierarchical pores in electrospun porous nanofibers can improve the reactive S reaction sites and block soluble polysulfides, thereby decreasing the "shuttling effect" of polysulfides during the electrochemical cycling. Second, electrospun porous fibers have excellent physical and mechanical properties, outstanding architecture, and superior electrical conductivity, which can enhance the transfer of Li-ions and electrons, endowing extraordinary electrochemical performance of the whole battery system. [20] Figure 2 shows phase and morphological evolutions of the electrospun nanofibers. By combining the electrospinning and other treatment (thermal, chem...

Miniaturization of energy conversion and storage devices has attracted remarkable consideration in the application of wearable electronics. Compared with film-based flexible electronics, fiber-based wearable electronics (e.g., nanogenerator and sensors made from electrospun nanofiber), are more appealing and promising for wearables. However, there are two bottlenecks, low power output, and poor sensing capability, limiting the application of piezoelectric nanofibers. Herein, we integrated zinc oxide nanorods (ZnO NRs) to a less known piezoelectric polymer, Polyacrylonitrile (PAN) nanofiber, forming a ZnO/PAN nano-fabric, which significantly improved the pressure sensitivity and vibrational energy harvesting ability by about 2.7 times compared with the pristine PAN nanofiber, and the maximum output power density of ∼10.8 mW• m -2 is achieved. Noteworthy, the ZnO/PAN nano-fabric showed a power output about twice of the one made of ZnO and polyvinylidene fluride (PVDF). It was revealed that the integration of ZnO NRs clearly improved the planar zig-zag conformation in microstructures of PAN nanofiber. Further, successful demonstrations of a mechanically robust pressure sensor and wearable power source confirms the potential applications in human activity monitoring and personal thermal management, respectively.

ObjectiveDrug shortages were a complex global problem. The aim of this study was to analyze, characterize, and assess the drug shortages, and identify possible solutions in Shaanxi Province, western China.MethodsA qualitative methodological approach was conducted during May–June 2015 and December 2015–January 2016. Semi-structured interviews were performed to gather information from representatives of hospital pharmacists, wholesalers, pharmaceutical producers, and local health authorities.ResultsThirty participants took part in the study. Eight traditional Chinese medicines and 87 types of biologicals and chemicals were reported to be in short supply. Most were essential medicines. Five main determinants of drug shortages were detected: too low prices, too low market demands, Good Manufacturing Practice (GMP) issues, materials issues, and approval issues for imported drugs. Five different solutions were proposed by the participants: 1) let the market decide the drug price; 2) establish an information platform; 3) establish a reserve system; 4) enhance the communication among the three parties in the supply chain; and 5) improve hospital inventory management.ConclusionsWestern China was currently experiencing a serious drug shortage. Numerous reasons for the shortage were identified. Most drug shortages in China were currently because of “too low prices.” To solve this problem, all of the stakeholders, especially the government, needed to participate in managing the drug shortages.

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